Combustor assembly

ABSTRACT

A combustor assembly for a gas turbine engine includes a combustor dome defining an opening, a cooling hole, and at least in part defining a combustion chamber. The combustor dome includes a first side and a second side, the cooling hole extending from the first side to the second side. The combustor assembly additionally includes a fuel-air injector hardware assembly positioned at least partially within the opening of the combustor dome and including a heat shield. The heat shield includes a heat deflector lip. The cooling hole in the combustor dome is oriented to direct a cooling airflow onto the heat deflector lip to maintain at least a portion of the heat shield within a desired operating temperature range.

FEDERALLY SPONSORED RESEARCH

This invention was made with government support under contract numberW911W6-11-2-0009 of the U.S. Army. The government may have certainrights in the invention.

FIELD OF THE INVENTION

The present subject matter relates generally to a gas turbine engine, ormore particularly to a combustor assembly for a gas turbine engine.

BACKGROUND OF THE INVENTION

A gas turbine engine generally includes a fan and a core arranged inflow communication with one another. Additionally, the core of the gasturbine engine general includes, in serial flow order, a compressorsection, a combustion section, a turbine section, and an exhaustsection. In operation, air is provided from the fan to an inlet of thecompressor section where one or more axial compressors progressivelycompress the air until it reaches the combustion section. Fuel is mixedwith the compressed air and burned within the combustion section toprovide combustion gases. The combustion gases are routed from thecombustion section to the turbine section. The flow of combustion gassesthrough the turbine section drives the turbine section and is thenrouted through the exhaust section, e.g., to atmosphere.

Within the combustion section, a combustor typically includes a fuel-airinjection assembly attached to a dome. The fuel-air injection assemblymay include a heat shield to protect, e.g., various other components ofthe fuel-air injection assembly and/or the dome. The heat shield thus issubjected to relatively high temperatures during operation of the gasturbine engine. Such exposure may cause premature wear and/or failure ofthe heat shield. Accordingly, a combustor capable of reducing prematurewear and/or failure of the heat shield would be useful.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In one exemplary embodiment of the present disclosure a combustorassembly for a gas turbine engine is provided. The combustor assemblyincludes a combustor dome defining an opening and a cooling hole, and atleast in part defining a combustion chamber. The combustor dome includesa first side and a second side. The cooling hole extends from the firstside to the second side. The combustor assembly further includes afuel-air injector hardware assembly positioned at least partially withinthe opening of the combustor dome and including a heat shield. The heatshield includes a heat deflector lip. The cooling hole in the combustordome is oriented to direct a cooling airflow onto the heat deflectorlip.

In another exemplary embodiment of the present disclosure, a combustorassembly for a gas turbine engine is provided. The combustor assemblyincludes a combustor dome defining an opening and a cooling hole, and atleast in part defining a combustion chamber. The combustor dome includesa first side and a second side. The cooling hole extends from the firstside to the second side. The combustor assembly additionally includes afuel-air injector hardware assembly positioned at least partially withinthe opening of the combustor dome and including a heat shield. The heatshield defines a circumferential channel, and the cooling hole in thecombustor dome is oriented to direct a cooling airflow into thecircumferential channel.

In one exemplary aspect of the present disclosure, a method for coolinga combustor of a gas turbine engine is provided. The combustor includinga combustor dome. The method includes providing a cooling airflow to acooling hole extending from a cold side of the combustor dome to a hotside of the combustor dome. The combustor dome defines an opening andthe combustor includes a fuel-air injector hardware assembly extendingat least partially through the opening. The method also includesdirecting the cooling airflow from the cooling hole to a cold side of aheat deflector lip of a heat shield of the fuel-air injector hardwareassembly. The heat deflector lip is located within a combustion chamberof the combustor.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 is a schematic cross-sectional view of an exemplary gas turbineengine according to various embodiments of the present subject matter.

FIG. 2 is a perspective view of a combustor assembly in accordance withan exemplary embodiment of the present disclosure.

FIG. 3 is a close-up view of a forward end of the exemplary combustorassembly of FIG. 2.

FIG. 4 is a perspective view of a section of the exemplary combustorassembly of FIG. 2.

FIG. 5 is a side, cross-sectional view of the exemplary combustorassembly of FIG. 2.

FIG. 6 is a close-up, perspective, cross-sectional view of a fuel-airinjector hardware assembly in accordance with an exemplary embodiment ofthe present disclosure attached to a combustor dome in accordance withan exemplary embodiment of the present disclosure.

FIG. 7 is a close-up, side, cross-sectional view of the exemplaryfuel-air injector hardware assembly attached to the exemplary combustordome of the exemplary combustor assembly of FIG. 2.

FIG. 8 is a close-up, perspective, cross-sectional view of a portion ofthe exemplary fuel-air injector hardware assembly attached the exemplarycombustor dome of the exemplary combustor assembly of FIG. 2.

FIG. 9 is a flow diagram of a method for cooling a combustor of a gasturbine engine in accordance with an exemplary embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to present embodiments of theinvention, one or more examples of which are illustrated in theaccompanying drawings. The detailed description uses numerical andletter designations to refer to features in the drawings. Like orsimilar designations in the drawings and description have been used torefer to like or similar parts of the invention. As used herein, theterms “first”, “second”, and “third” may be used interchangeably todistinguish one component from another and are not intended to signifylocation or importance of the individual components. The terms“upstream” and “downstream” refer to the relative direction with respectto fluid flow in a fluid pathway. For example, “upstream” refers to thedirection from which the fluid flows, and “downstream” refers to thedirection to which the fluid flows.

Referring now to the drawings, wherein identical numerals indicate thesame elements throughout the figures, FIG. 1 is a schematiccross-sectional view of a gas turbine engine in accordance with anexemplary embodiment of the present disclosure. More particularly, forthe embodiment of FIG. 1, the gas turbine engine is a high-bypassturbofan jet engine 10, referred to herein as “turbofan engine 10.” Asshown in FIG. 1, the turbofan engine 10 defines an axial direction A(extending parallel to a longitudinal centerline 12 provided forreference), a radial direction R, and a circumferential direction (notshown) extending about the axial direction A. In general, the turbofan10 includes a fan section 14 and a core turbine engine 16 disposeddownstream from the fan section 14.

The exemplary core turbine engine 16 depicted generally includes asubstantially tubular outer casing 18 that defines an annular inlet 20.The outer casing 18 encases and the core turbine engine 16 includes, inserial flow relationship, a compressor section including a booster orlow pressure (LP) compressor 22 and a high pressure (HP) compressor 24;a combustion section 26; a turbine section including a high pressure(HP) turbine 28 and a low pressure (LP) turbine 30; and a jet exhaustnozzle section 32. A high pressure (HP) shaft or spool 34 drivinglyconnects the HP turbine 28 to the HP compressor 24. A low pressure (LP)shaft or spool 36 drivingly connects the LP turbine 30 to the LPcompressor 22. The compressor section, combustion section 26, turbinesection, and nozzle section 32 together define a core air flowpath 37.

For the embodiment depicted, the fan section 14 includes a variablepitch fan 38 having a plurality of fan blades 40 coupled to a disk 42 ina spaced apart manner. As depicted, the fan blades 40 extend outwardlyfrom disk 42 generally along the radial direction R. Each fan blade 40is rotatable relative to the disk 42 about a pitch axis P by virtue ofthe fan blades 40 being operatively coupled to a suitable pitch changemechanism 44 configured to collectively vary the pitch of the fan blades40 in unison. The fan blades 40, disk 42, and pitch change mechanism 44are together rotatable about the longitudinal axis 12 by LP shaft 36across a power gear box 46. The power gear box 46 includes a pluralityof gears for adjusting the rotational speed of the fan 38 relative tothe LP shaft 36 to a more efficient rotational fan speed.

Referring still to the exemplary embodiment of FIG. 1, the disk 42 iscovered by a rotatable front hub 48 aerodynamically contoured to promotean airflow through the plurality of fan blades 40. Additionally, theexemplary fan section 14 includes an annular fan casing or outer nacelle50 that circumferentially surrounds the fan 38 and/or at least a portionof the core turbine engine 16. The exemplary nacelle 50 is supportedrelative to the core turbine engine 16 by a plurality ofcircumferentially-spaced outlet guide vanes 52. Moreover, a downstreamsection 54 of the nacelle 50 extends over an outer portion of the coreturbine engine 16 so as to define a bypass airflow passage 56therebetween.

During operation of the turbofan engine 10, a volume of air 58 entersthe turbofan 10 through an associated inlet 60 of the nacelle 50 and/orfan section 14. As the volume of air 58 passes across the fan blades 40,a first portion of the air 58 as indicated by arrows 62 is directed orrouted into the bypass airflow passage 56 and a second portion of theair 58 as indicated by arrow 64 is directed or routed into the core airflowpath 37, or more specifically into the LP compressor 22. The ratiobetween the first portion of air 62 and the second portion of air 64 iscommonly known as a bypass ratio. The pressure of the second portion ofair 64 is then increased as it is routed through the high pressure (HP)compressor 24 and into the combustion section 26, where it is mixed withfuel and burned to provide combustion gases 66.

The combustion gases 66 are routed through the HP turbine 28 where aportion of thermal and/or kinetic energy from the combustion gases 66 isextracted via sequential stages of HP turbine stator vanes 68 that arecoupled to the outer casing 18 and HP turbine rotor blades 70 that arecoupled to the HP shaft or spool 34, thus causing the HP shaft or spool34 to rotate, thereby supporting operation of the HP compressor 24. Thecombustion gases 66 are then routed through the LP turbine 30 where asecond portion of thermal and kinetic energy is extracted from thecombustion gases 66 via sequential stages of LP turbine stator vanes 72that are coupled to the outer casing 18 and LP turbine rotor blades 74that are coupled to the LP shaft or spool 36, thus causing the LP shaftor spool 36 to rotate, thereby supporting operation of the LP compressor22 and/or rotation of the fan 38.

The combustion gases 66 are subsequently routed through the jet exhaustnozzle section 32 of the core turbine engine 16 to provide propulsivethrust. Simultaneously, the pressure of the first portion of air 62 issubstantially increased as the first portion of air 62 is routed throughthe bypass airflow passage 56 before it is exhausted from a fan nozzleexhaust section 76 of the turbofan 10, also providing propulsive thrust.The HP turbine 28, the LP turbine 30, and the jet exhaust nozzle section32 at least partially define a hot gas path 78 for routing thecombustion gases 66 through the core turbine engine 16.

It should be appreciated, however, that the exemplary turbofan engine 10depicted in FIG. 1 is provided by way of example only, and that in otherexemplary embodiments, the turbofan engine 10 may have any othersuitable configuration. It should also be appreciated, that in stillother exemplary embodiments, aspects of the present disclosure may beincorporated into any other suitable gas turbine engine. For example, inother exemplary embodiments, aspects of the present disclosure may beincorporated into, e.g., a turboprop engine, a turboshaft engine, aturbojet engine, or a power generation gas turbine engine.

Referring now to FIGS. 2 through 4, views are provided of a combustorassembly 100 for a gas turbine engine in accordance with an exemplaryembodiment of the present disclosure. For example, the combustorassembly 100 of FIGS. 2 through 4 may be positioned in the combustionsection 26 of the exemplary turbofan engine 10 of FIG. 1, which definesan axial direction A, a radial direction R, and a circumferentialdirection C. More particularly, FIG. 2 provides a perspective view ofthe combustor assembly 100; FIG. 3 provides a close-up view of a forwardend of the combustor assembly 100 of FIG. 2; and FIG. 4 provides aperspective, cross-sectional view of a section of the exemplarycombustor assembly 100 of FIG. 2.

As shown, the combustor assembly 100 defines a centerline 101 andgenerally includes a combustor dome 102 and a combustion chamber liner.When assembled in a gas turbine engine, the centerline 101 of thecombustor assembly 100 aligns with a centerline of the gas turbineengine (see, centerline 12 of FIG. 1). For the embodiment depicted, thecombustion chamber liner is configured as a combustion chamber outerliner 104, and the combustor dome 102 and combustion chamber outer liner104 are formed integrally. Additionally, the combustor assembly 100includes a combustion chamber inner liner 106 (see FIG. 4). Thecombustor dome 102, combustion chamber outer liner 104, and combustionchamber inner liner 106 each extend along the circumferential directionC. More particularly, the combustor dome 102, combustion chamber outerliner 104, and combustion chamber inner liner 106 each extendcontinuously along the circumferential direction C to define an annularshape, without any seams or joints where multiple pieces would otherwisebe combined. The combustor dome 102, combustion chamber outer liner 104,and combustion chamber inner liner 106 at least partially define acombustion chamber 108. The combustion chamber 108 also extends alongthe circumferential direction to define an annular shape. Accordingly,the combustor assembly 100 may be referred to as an annular combustor.

Referring still to FIGS. 2 through 4, for the embodiment depicted thecombustor dome 102, combustion chamber inner liner 106, and combustionchamber outer liner 104 are each formed of a ceramic matrix composite(“CMC”) material. CMC material is a non-metallic material having hightemperature capability. Exemplary CMC materials utilized for thecombustor dome 102 and combustion chamber liners (e.g., the outer liner104 and inner liner 106) may include silicon carbide, silicon, silica oralumina matrix materials and combinations thereof. Ceramic fibers may beembedded within the matrix, such as oxidation stable reinforcing fibersincluding monofilaments like sapphire and silicon carbide (e.g.,Textron's SCS-6), as well as rovings and yarn including silicon carbide(e.g., Nippon Carbon's NICALON®, Ube Industries' TYRANNO®, and DowCorning's SYLRAMIC®), alumina silicates (e.g., Nextel's 440 and 480),and chopped whiskers and fibers (e.g., Nextel's 440 and SAFFIL®), andoptionally ceramic particles (e.g., oxides of Si, Al, Zr, Y andcombinations thereof) and inorganic fillers (e.g., pyrophyllite,wollastonite, mica, talc, kyanite and montmorillonite).

It should be appreciated, however, that in other embodiments, thecombustion chamber outer liner 104 and combustor dome 102 may not beformed integrally, and instead may be joined in any other suitablemanner. Additionally, in other embodiments, the combustor dome 102,combustion chamber inner liner 106, and combustion chamber outer liner104 may not extend continuously along the circumferential direction Cand instead may be formed of a plurality of individual components.Further, in still other embodiments, one or more of the combustor dome102, combustion chamber inner liner 106, and combustion chamber outerliner 104 may be formed of any other suitable material, such as a metalmaterial, and may include one or more coatings, such as an environmentalbarrier coating.

Referring to FIG. 4 in particular, the combustion chamber outer liner104 and combustion chamber inner liner 106 each extend generally alongthe axial direction A—the combustion chamber outer liner 104 extendingbetween a forward end 110 and an aft end 112 and the combustion chamberinner liner 106 similarly extending between a forward end 114 and an aftend 116. Additionally, the combustor dome 102 includes a forward wall118 and a transition portion. Specifically, the combustor dome 102depicted includes an outer transition portion 120 and an innertransition portion 122. The outer transition portion 120 is positionedalong an outer edge of the forward wall 118 along the radial direction Rand the inner transition portion 122 is positioned along an inner edgeof the forward wall 118 along the radial direction R. The inner andouter transition portions 122, 120 each extend circumferentially withthe forward wall 118 of the combustor dome 102 (see a FIG. 2).

Further, the outer transition portion 120 extends from the forward wall118 towards the outer liner 104 and the inner transition portion 122extends from the forward wall 118 towards the inner liner 106. Asstated, for the embodiment depicted the outer liner 104 is formedintegrally with the combustor dome 102 (including the forward wall 118and the outer transition portion 120), and thus the outer transitionportion 120 extends seamlessly from the forward wall 118 to the outerliner 104. For example, the combustor dome 102 and combustion chamberouter liner 104 together define a continuous and seamless surfaceextending from the combustor dome 102 to the combustion chamber outerliner 104.

By contrast, the combustion chamber inner liner 106 is formed separatelyfrom the combustor dome 102 and combustion chamber outer liner 104. Thecombustion chamber inner liner 106 is attached to the combustor dome 102using a mounting assembly 124. The mounting assembly 124 for theembodiment depicted generally includes a support member 126 extendingsubstantially continuously along the circumferential direction C and aplurality of brackets 128. The support member 126 includes a flange 130at a forward end 132. The flange 130 of the support member 126 and aplurality of brackets 128 are disposed on opposite sides of a couplingflange 134 of the combustor dome 102 and a coupling flange 136 of theinner combustion chamber inner liner 106. An attachment member 138, ormore particularly, a bolt and nut press the flange 132 of the supportmember 126 and the plurality of brackets 128 together to attach thecombustor dome 102 and combustion chamber inner liner 106. Additionally,the support member 126 extends to an aft end 140, the aft end 140including a mounting flange 142 for attachment to a structural componentof the gas turbine engine, such as a casing or other structural member.Accordingly, the combustion chamber outer liner 104, combustor dome 102,and combustion chamber inner liner 106 may each be supported within thegas turbine engine at a forward end of the combustor assembly 100 (i.e.,at the forward end 114 of the inner liner 106) through the supportmember 126 of the mounting assembly 124.

As will be described in greater detail below with reference to FIGS. 5through 7, the combustor dome 102 additionally defines an opening 144and the combustor assembly 100 includes a fuel-air injector hardwareassembly 146. More particularly, the combustor dome 102 defines aplurality of openings 144 and the combustor assembly 100 includes arespective plurality of fuel-air injector hardware assemblies 146—eachopening 144 configured to receive a respective one of the plurality offuel-air injector hardware assemblies 146. For the embodiment depicted,each of the openings 144 are substantially evenly spaced along thecircumferential direction C. Referring specifically to FIG. 3, each ofthe openings 144 defined by the combustor dome 102 includes a center148, and the combustor dome 102 defines a spacing S measured along thecircumferential direction C from the center 148 of one opening 144 to acenter 148 of an adjacent opening 144. Accordingly, as depicted, thespacing S may be defined as an arc length between the center 148 of oneopening 144 and the center 148 of an adjacent opening 144. Further,although the fuel-air injector hardware assemblies 146 are depictedschematically in FIGS. 2 and 3, a centerline 149 (see FIG. 5) of thefuel-air injector hardware assemblies 146 may pass through the center148 of the opening 144 through which it extends. Accordingly, in certainexemplary embodiments, the spacing S may also be defined as a distancealong the circumferential direction C between the centerlines 149 ofadjacent fuel-air injector hardware assemblies 146 (and morespecifically between portions of the centerlines 149 passing through therespective openings 144). The spacing S may be consistent for each ofthe plurality of openings 144.

Generally, the fuel-air injector hardware assemblies 146 are configuredto receive a flow of combustible fuel from a fuel nozzle (not shown) andcompressed air from a compressor section of a gas turbine engine inwhich the combustor assembly 100 is installed (see FIG. 1). The fuel-airinjector hardware assemblies 146 mix the fuel and compressed air andprovide such fuel-air mixture to the combustion chamber 108. As willalso be discussed in greater detail below, each of the fuel air injectorhardware assemblies 146 include components for attaching the assemblydirectly to the combustor dome 102. Notably, for the embodimentdepicted, such components of each of the plurality of fuel-air injectorhardware assemblies 146 are configured such that one or more of theassemblies are attached to the combustor dome 102 independently of anadjacent fuel-air injector hardware assembly 146. More particularly, forthe embodiment depicted, each fuel-air injector hardware assembly 146 isattached to the combustor dome 102 independently of each of the otherfuel-air injector hardware assemblies 146. Accordingly, no part of thefuel-air injector hardware assemblies 146 are attached to the adjacentfuel-air injector hardware assemblies 146, except through the combustordome 102. Such a configuration is enabled at least in part by theconfiguration of the exemplary combustor dome 102 extendingsubstantially continuously along the circumferential direction C.

As may also be seen in FIGS. 2 through 4, the combustor dome 102generally includes a first side, or a cold side 150, and a second side,or a hot side 152, the hot side 152 being exposed to the combustionchamber 108. The combustor dome 102 defines a plurality of cooling holes154 extending from the cold side 150 to the hot side 152 to allow for aflow of cooling air therethrough. As may be seen, the plurality ofcooling holes 154 includes a plurality of cooling holes 154 extendingaround each of the openings 144 defined by the combustor dome 102, orrather spaced around a circumference of each of the openings 144 definedby the combustor dome 102. Such cooling holes 154 may be configured toprovide a flow of cooling air to certain components of the fuel-airinjector hardware assemblies 146 located within the combustion chamber108.

Referring now to FIGS. 5 through 7, additional views of the exemplarycombustor assembly 100 of FIG. 2 are provided. Specifically, FIG. 5provides a side, cross-sectional view of the exemplary combustorassembly 100 of FIG. 2; FIG. 6 provides a perspective, cross-sectionalview of the fuel-air injector hardware assembly 146 attached thecombustor dome 102; and FIG. 7 provides a side, cross-sectional view ofthe exemplary fuel-air injector hardware assembly 146 attached thecombustor dome 102.

With reference specifically to FIG. 5, an exemplary fuel-air injectorhardware assembly 146 extending at least partially through a respectiveone of the plurality of openings 144 defined by the combustor dome 102is more clearly depicted. The exemplary fuel-air injector hardwareassembly 146 defines a centerline 149 and generally includes a firstmember positioned at least partially adjacent to the cold side 150 ofthe combustor dome 102 and a second member positioned at least partiallyadjacent to the hot side 152 of the combustor dome 102. The first andsecond members together define an attachment interface 168 joining thefirst member to the second member and mounting the fuel-air injectorhardware assembly 146 to the combustor dome 102. Moreover, theattachment interface 168 is shielded from (i.e., not directly exposedto) the combustion chamber 108 to protect the attachment interface 168from relatively hot operating temperatures within the combustion chamber108. For the embodiment depicted, the first member is a seal plate 156and the second member is a heat shield 158. The fuel-air injectorhardware assembly 146 further includes a swirler 160, the swirler 160attached to the seal plate 156, e.g., by welding. The heat shield 158,seal plate 156, and swirler 160 may each be formed of a metal material,such as a metal alloy material.

The heat shield 158 defines an outer diameter D_(HS), or moreparticularly, the heat shield 158 includes a heat deflector lip 162positioned substantially within the combustion chamber 108 and definingthe outer diameter D_(HS). The heat deflector lip 162 is configured toprotect or shield at least a portion of the fuel-air injector hardwareassembly 146 from the relatively high temperatures within the combustionchamber 108 during operation. Notably, the heat deflector lip 162generally includes a cold side 164 facing back towards the forward wall118 of the combustor dome 102 and a hot side 166 facing downstream. Theheat shield 158, or rather the heat deflector lip 162, may include anenvironmental barrier coating, or other suitable protective coating, onthe hot side 166 (not shown).

For the embodiment depicted, the heat shield 158 is a relatively smallheat shield 158 as compared to an overall size of the combustor assembly100, and more particularly, as compared to a size of the combustionchamber 108 and the forward wall 118 of the combustor dome 102 of thecombustor assembly 100. For example, the combustion chamber 108 includesan annulus height H_(A) defined between the inner liner 106 and theouter liner 104. Specifically, the forward wall 118 of the combustordome 102 defines a direction D_(FW) intersecting with a centerline 101of the combustor assembly 100, and for the embodiment depicted, theannulus height H_(A) is defined in a direction parallel to the directionD_(FW) of the forward wall 118 of the combustor dome 102. Additionally,the direction D_(FW) of the forward wall 118 is orthogonal to thecenterline 149 of the fuel-air injector hardware assembly 146. A ratioof the annulus height H_(A) of the combustion chamber 108 to the outerdiameter D_(HS) of the heat shield 158 (“H_(A):D_(HS)”) is at leastabout 1.3:1. For example, the ratio H_(A):D_(HS) of the annulus heightH_(A) of the combustion chamber 108 to the outer diameter D_(HS) of theheat shield 158 may be at least about 1.4:1, at least about 1.5:1, atleast about 1.6:1, or up to about 1.8:1. As used herein, terms ofapproximation, such as “about” or “approximate,” refer to being within a10% margin of error.

Moreover, the exemplary forward wall 118 of the combustor dome 102defines a length L_(FW) along the direction D_(FW) of the forward wall118. For the embodiment depicted, the length L_(FW) of the forward wall118 is defined from a first bend 121 between the transition portion 120and the forward wall 118 and a first bend 123 between the transitionportion 122 and the forward wall 118. A ratio of the length L_(FW) ofthe forward wall 118 to the outer diameter D_(HS) of the heat shield 158(“L_(FW):D_(HS)”) is at least about 1.1:1. For example, the ratioL_(FW):D_(HS) of the length L_(FW) of the forward wall 118 to the outerdiameter D_(HS) of the heat shield 158 may be at least about 1.15:1, atleast about 1.2:1, or between 1.1:1 and 1.5:1.

Further, as described above with respect to FIG. 2, the combustorassembly 100 defines a spacing S from a center 148 of one opening 144 toa center 148 of an adjacent opening 144 measured along thecircumferential direction C (see FIG. 2). For the embodiment depicted, aratio of the spacing S to the outer diameter D_(HS) of the heat shield158 (“S:D_(HS)”) is at least about 1.3:1. For example, the ratioS:D_(HS) of the spacing S of the plurality of openings 144 to the outerdiameter D_(HS) of the heat shield 158 may be at least about 1.4:1, atleast about 1.5:1, at least about 1.7:1, or up to about 1.9:1.

Accordingly, with such a configuration, the combustor dome 102 may berelatively exposed to the operating temperatures within the combustionchamber 108 during operation of the combustor assembly 100. However, thereduced footprint of the heat shield 158 may result in a lighter overallcombustor assembly 100. Additionally, the inventors of the presentdisclosure have discovered that given that the combustor dome 102 may beformed of a CMC material, the combustor dome 102 may be well-suited forwithstanding such elevated temperatures.

Despite having a reduced footprint, the heat shield 158 may stillprotect the various other metal components of the fuel-air injectorhardware assembly 146. For example, referring still to FIG. 5, the sealplate 156 and swirler 160 of the fuel-air injector hardware assembly 146define a maximum outer diameter D_(MAX) (see also FIG. 7, below). Themaximum outer diameter D_(MAX) of the seal plate 156 and swirler 160 isless than or equal to the outer diameter D_(HS) of the heat shield 158.For example, in certain exemplary embodiments, a ratio of the outerdiameter D_(HS) of the heat shield 158 to the maximum outer diameterD_(MAX) of the swirler 160 and seal plate 156 (“D_(HS):D_(MAX)”) may bebetween about 1:1 and about 1.1:1.

Referring now particularly to FIGS. 6 and 7, as previously discussed,the fuel-air injector hardware assembly 146 includes a first member, orseal plate 156, and a second member, or heat shield 158. The fuel-airinjector hardware assembly 146 additionally includes the swirler 160,which as used herein refers generally to the various components providedfor receiving and mixing flows of fuel and air, as well for providingsuch mixture to the combustion chamber 108.

The seal plate 156 is positioned at least partially adjacent to the coldside 150 of the combustor dome 102 and the heat shield 158 is positionedat least partially adjacent to the hot side 152 of the combustor dome102. The seal plate 156 and heat shield 158 are joined to one another tomount the fuel-air injector hardware assembly 146 to the combustor dome102. Specifically, as stated above, the seal plate 156 and heat shield158 together define the attachment interface 168. In certain exemplaryembodiments, the seal plate 156 may be rotatably engaged with the heatshield 158, and thus the attachment interface 168 may be a rotatableattachment interface formed of complementary threaded surfaces of theseal plate 156 and the heat shield 158.

Particularly for the embodiment depicted, the seal plate 156 defines afirst flange 170 positioned adjacent to the cold side 150 of thecombustor dome 102 and the heat shield 158 includes a second flange 172positioned adjacent to the hot side 152 of the combustor dome 102.During assembly, the heat shield 158 and seal plate 156 may be tightenedat the attachment interface 168 to a desired clamping force (i.e., to aspecific torque when the attachment interface 168 is a rotatableattachment interface 168) for the given combustor assembly 100.Accordingly, the first and second flanges 170, 172 are pressed towardseach other (against the combustor dome 102) when assembled such thatthey are attached to the combustor dome 102. The swirler 160 and/orother components of the fuel-air injector hardware assembly 146 may thenbe attached to, e.g., the seal plate 156 by welding or in any othersuitable manner. Additionally, once assembled, the seal plate 156 may bewelded to the heat shield 158 at the attachment interface 168 to preventloosening of the seal plate 156 relative to the heat deflector (i.e., toprevent rotation of the seal plate 156 relative to the heat shield 158).It should be appreciated, however, that the swirler 160 and/or othercomponents of the fuel-air injector hardware assembly 146 may beattached to, e.g., the seal plate 156 in any other suitable manner, suchas by using a mechanical fastener or other mechanical fastening means.

Further, referring briefly to FIG. 8, providing a close-up, perspective,cross-sectional view of a portion of the seal plate 156 and combustordome 102. The seal plate 156 defines a slot 174 and the combustor dome102 additionally defines a slot 176. The fuel-air injector hardwareassembly 146 includes a pin 178 extending through the slot 174 in theseal plate 156 and into the slot 176 in the combustor dome 102. The pin178 may be a cylindrical, metal pin, or alternatively, may have anyother suitable shape and may be configured of any other suitablematerial. Regardless, the pin 178 may prevent rotation of the seal plate156 relative to the combustor dome 102. The pin 178 may be welded orotherwise affixed to the seal plate 156, e.g., prior to installation ofthe of the seal plate 156, or once the seal plate 156 and pin 178 are inposition.

Referring still to the embodiment of FIGS. 6 and 7, the first flange 170is positioned directly against the cold side 150 of the combustor dome102 and the second flange 172 is positioned directly against the hotside 152 of the combustor dome 102. Accordingly, no intermediarycomponents are required between e.g., the seal plate 156 and combustordome 102 or heat shield 158 and combustor dome 102 for mounting thefuel-air injector hardware assembly 146. Notably, the combustor dome 102includes a raised boss 180 (FIG. 7) extending around a circumference ofthe opening 144 in the combustor dome 102 on the cold side 150 toprovide a desired thickness and additional strength for an attachmentportion of the combustor dome 102 around the opening 144 defined in thecombustor dome 102. Additionally, the combustor dome 102 includes arecess 181 extending around a circumference of the opening 144 in thecombustor dome 102 on the hot side 152 to receive the flange 172 of theheat shield 158. It should be appreciated, however, that in certainembodiments, the combustor assembly 100 may include an intermediatecomponent between the first and second flanges 170, 172 and thecombustor dome 102.

Also for the embodiment depicted, the combustor dome 102 is formed of aCMC material, while the fuel-air injector hardware assembly 146 isformed of a metal material, such as metal alloy material. In order toprevent thermal expansion relative to the combustor dome 102 beyond adesired amount (i.e., thermal expansion of the portions of the sealplate 156 and heat shield 158 attaching the fuel-air injector hardwareassembly 146 to the combustor dome 102), the attachment interface 168defined by the seal plate 156 and heat shield 158 is positioned at leastpartially in the opening 144 of the combustor dome 102. With such aconfiguration, the attachment interface 168 may be protected by the heatshield 158 and/or other components of the fuel-air injector hardwareassembly 146. For example, the heat shield 158 may be configured toprotect or shield the attachment interface 168 from an amount of heat inthe combustion chamber 108 during operation of the combustor assembly100. Accordingly, the components attaching the fuel-air injectorhardware assembly 146 to the combustor dome 102 may be prevented fromthermal expansion beyond a desired amount during operation of thecombustor assembly 100, such that the attachment of the fuel-airinjector hardware assembly 146 to the combustor dome 102 remains intactduring operation of the combustor assembly 100.

Furthermore, in order to maintain the heat shield 158 within a desiredoperating temperature range during operation of the combustor assembly100, in addition to protecting the attachment interface 168, thecombustor dome 102 is configured to provide a cooling airflow to theheat shield 158 during operation of the combustor assembly 100. Asstated, the combustor dome 102 includes a cooling hole 154 extendingthrough the combustor dome 102. Specifically, for the embodimentdepicted, the cooling hole 154 is oriented to direct a cooling airflowonto the heat deflector lip 162 of the heat shield 158, or rather ontothe cold side 164 of the heat deflector lip 162 of the heat shield 158.For example, the exemplary cooling hole 154 depicted slants towards theopening 144 in the combustor dome 102 from the cold side 150 of thecombustor dome 102 to the hot side 152 of the combustor dome 102 (i.e.,slants towards the opening 144 as it extends from the cold side 150 ofthe combustor dome 102 to the hot side 152 of the combustor dome 102).Further, the cooling hole 154 includes an outlet 182 at the hot side 152of the combustor dome 102, and for the embodiment depicted, the heatdeflector lip 162 of the heat shield 158 covers the outlet 182 of thecooling hole 154 in the combustor dome 102. For example, at least aportion of the heat deflector lip 162 extends farther out than at leasta portion of the outlet 182 of the cooling hole 154 relative to thecenter 148 of the opening 144. For example, in the cross-sectiondepicted in FIG. 5, the heat deflector lip 163 extends farther out thanat least a portion of the outlets 182 of the cooling holes 154 depictedrelative to the center 148 of the opening 144 in a direction parallel tothe direction D_(FW) of the forward wall 118 of the combustor dome 102.With such a configuration, at least a majority of airflow through thecooling hole 154 must flow onto the cold side 164 of the heat deflectorlip 162.

Particularly for the embodiment depicted, the cold side 164 of the heatdeflector lip 162 of the heat shield 158 at least partially defines achannel 184. Specifically, the channel 184 is defined by the cold side164 of the heat deflector lip 162 along with the second flange 172 ofthe heat shield 158 and a portion of the hot side 152 of the combustordome 102. For the embodiment depicted, the heat deflector lip 162extends in a circular direction that is similar in shape to thecircumference of the opening 144 in the combustor dome 102. Accordingly,the channel 184 may be referred to as a circumferential channel.

During operation of the combustor assembly 100 a cooling airflow isprovided through the cooling hole 154 in the combustor dome 102 and, dueto the orientation of the cooling hole 154, the cooling airflow isprovided into the channel 184 such that the channel 184 receives thecooling airflow. In certain embodiments, the cooling airflow mayoriginate from a compressor section of the gas turbine engine into whichthe combustor assembly 100 is installed (see FIG. 1). The coolingairflow may remove an amount of heat from the heat deflector lip 162 tomaintain the heat shield 158 within a desired operating temperaturerange. Additionally, the cooling airflow may maintain the componentsattaching the fuel-air injector hardware assembly 146 to the combustordome 102 within a desired operating temperature range. As is depicted,the exemplary channel 184 depicted defines a U-shape. The channel 184may thus redirect the cooling airflow from the cooling hole 154 alongthe hot side 152 of the combustor dome 102 and downstream to begin acooling flow for the combustor dome 102 as well. However, in otherembodiments, the channel 184 may have any other suitable shape forproviding such functionality, if desired.

In order to ensure the above functionalities are achieved by the channel184, the channel 184 may define at least a minimum height D_(C). Inparticular, the channel 184 may define the height D_(C) in a directionperpendicular to the direction D_(FW) of the forward wall 118 of thecombustor dome 102 (see FIG. 5). The height D_(C) of the channel 184 isdependent on an anticipated amount of cooling air through the channel184 to maintain a velocity of the cooling air in the channel 184 above athreshold value. For example, in certain embodiments the height D_(C) ofthe channel 184 may be at least about 0.010 inches, such as at leastabout 0.025 inches, such as at least about 0.050 inches, or any othersuitable height.

Notably, as previously stated the combustor dome 102 may further includea plurality of cooling holes 154 spaced along a circumference of theopening 144 in the combustor dome 102. Specifically, the combustor dome102 may further include a plurality of cooling holes 154 oriented todirect a cooling airflow onto the cold side 164 of the heat deflectorlip 162. Such a configuration may further ensure the heat shield 158 ismaintained within a desired operating temperature range during operationof the combustor assembly 100, and/or that the components attaching thefuel-air injector hardware assembly 146 to the combustor dome 102 remainwithin a desired operating temperature range.

A combustor assembly in accordance with one or more embodiments of thepresent disclosure may provide for an efficient means for attaching afuel-air injector hardware assembly, formed generally of a metalmaterial, to a combustor dome, which may be formed generally of a CMCmaterial. Additionally, with such a configuration the heat shield may besized to provide a desired amount of protection from the relatively hightemperatures within the combustion chamber during operation of thecombustor assembly, without being excessively large and/or withoutadding an undue amount of weight to the combustor assembly. Further, afuel-air injector hardware assembly including one or more features ofthe present disclosure may allow for heat shield to provide a desiredamount of protection from the relatively high temperatures within thecombustion chamber while being maintained within a desired operatingtemperature range and while maintaining the components attaching thefuel-air injector hardware assembly 146 to the combustor dome 102 withina desired operating temperature range. Further still, inclusion of aplurality of cooling holes through the combustor dome may allow for amore compact fuel-air injector hardware assembly, as a fuel-air injectorhardware assembly would not be required to make room for cooling airflowtherethrough. Additionally, providing cooling airflow through thecombustor dome may allow for better source pressure (as opposed toflowing the cooling air through the fuel-air injector hardwareassembly).

It should be appreciated, however, that the combustor assembly 100, andparticularly the combustor dome 102 and the fuel-air injector hardwareassembly 146, are provided by way of example only, and that otherembodiments may have any other suitable configuration. For example, inother exemplary embodiments, the fuel-air injector hardware assembly 146may be attached to the combustor dome 102 in any other suitable manner,the heat shield 158 of the fuel-air injector hardware assembly 146 mayhave any other suitable configuration, and similarly, the combustor dome102 may have any other suitable configuration.

Referring now to FIG. 9, a flow diagram is provided of a method (200)for cooling a combustor of a gas turbine engine. The exemplary method(200) may be utilized with one or more of the exemplary gas turbineengines described above with reference to one or more of FIGS. 1 through8. Accordingly, the combustor may include a combustor dome and afuel-air injector hardware assembly. The combustor dome may define anopening and the fuel-air injector hardware assembly may extend at leastpartially through the opening.

The exemplary method (200) depicted generally includes at (202)providing a cooling airflow through a cooling hole extending from a coldside of the combustor dome to a hot side of the combustor dome.Additionally, the exemplary method (200) includes at (204) directing thecooling airflow from the cooling hole to a cold side of a heat deflectorlip of a heat shield of the fuel-air injector hardware assembly. Thecold side of the heat deflector lip is located within a combustionchamber of the combustor. More specifically, for the embodimentdepicted, directing the cooling airflow from the cooling hole to thecold side of the heat deflector lip at (204) includes at (206) directingthe airflow from the cooling hole to a channel defined at least in partby the heat deflector lip of the heat shield.

Referring still to FIG. 9 the exemplary method (200) additionallyincludes at (208) redirecting the cooling airflow from the channel alongthe hot side of the combustor dome to form a cooling film along the hotside of the combustor dome. Moreover, the exemplary method (200)includes at (210) providing additional cooling airflow to the coolingfilm along the hot side of the combustor dome through one or moreadditional cooling holes defined by the combustor dome.

A combustor operated in accordance with one or more aspects of theexemplary method (200) described above with reference to FIG. 9 mayallow for starting and maintaining a cooling film of cooling air alongthe hot side of the combustor dome, to assist with maintaining thecombustor dome within a desired temperature range.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A combustor assembly for a gas turbine engine,the combustor assembly comprising: a combustor dome defining an openingand a cooling hole, and at least partially defining a combustionchamber, the combustor dome comprising a first side and a second side,the cooling hole extending from the first side to the second side; and afuel-air injector hardware assembly positioned at least partially withinthe opening of the combustor dome and comprising a heat shield, the heatshield comprising a heat deflector lip, and the cooling hole in thecombustor dome oriented to direct a cooling airflow onto the heatdeflector lip, wherein the fuel-air injector hardware assembly defines acenterline; wherein the heat shield further comprises a flange, whereina surface of the flange and the heat deflector lip of the heat shielddefine a channel therebetween configured to receive a cooling airflowfrom the cooling hole, wherein the cooling hole is oriented to directthe cooling airflow into the channel, wherein the cooling hole includesan inlet at the first side of the combustor dome and an outlet at thesecond side of the combustor dome, wherein the heat deflector lipdefines an outer tip, and wherein the inlet is positioned a firstdistance from the centerline and the outer tip of the heat deflector lipis positioned a second distance from the centerline of the fuel-airinjector hardware assembly, wherein the first distance is greater thanthe second distance; and wherein the surface of the flange is flush withthe second side of the combustor dome.
 2. The combustor assembly ofclaim 1, wherein the cooling hole slants towards the opening in thecombustor dome from the first side of the combustor dome to the secondside of the combustor dome.
 3. The combustor assembly of claim 1,wherein the cooling hole is a first cooling hole of a plurality ofcooling holes extending from the first side of the combustor dome to thesecond side of the combustor dome oriented to direct a cooling airflowonto the heat deflector lip.
 4. The combustor assembly of claim 3,wherein the combustor dome defines a circumference extending around theopening, and wherein the plurality of cooling holes are spaced along thecircumference extending around the opening.
 5. The combustor assembly ofclaim 1, wherein the heat deflector lip comprises a hot side and a coldside, and wherein the cooling hole in the combustor dome is oriented todirect the cooling airflow onto the cold side of the heat deflector lip.6. The combustor assembly of claim 5, wherein the cold side of the heatdeflector lip of the heat shield at least partially defines the channel.7. The combustor assembly of claim 5, wherein the channel defines aU-shape.
 8. The combustor assembly of claim 5, wherein the combustordome comprises a forward wall, wherein the forward wall of the combustordome defines a direction, wherein the channel defined by the heatdeflector lip and the flange defines a height in a directionperpendicular to the direction of the forward wall of the combustordome, and wherein the height of the channel is at least about 0.025inches.
 9. The combustor assembly of claim 1, wherein the second side ofthe combustor dome is a hot side, and wherein the heat deflector lip ofthe heat shield at least partially covers the outlet of the cooling holein the combustor dome such that the outer tip of the heat deflector lipis located outward of the outlet of the cooling hole relative to thecenterline of the fuel-air injector hardware assembly.
 10. The combustorassembly of claim 1, wherein the combustor dome is formed of a ceramicmatrix composite material.
 11. A combustor assembly for a gas turbineengine, the combustor assembly defining a centerline comprising: acombustor dome defining an opening and a cooling hole, and at least inpart defining a combustion chamber, the combustor dome comprising afirst side and a second side, the cooling hole extending from the firstside to the second side; and a fuel-air injector hardware assemblypositioned at least partially within the opening of the combustor domeand comprising a heat shield, the heat shield defining a circumferentialchannel, the cooling hole in the combustor dome oriented to direct acooling airflow into the circumferential channel; wherein the heatshield comprises a heat deflector lip and a flange, wherein a surface ofthe flange and the heat deflector lip of the heat shield define thechannel therebetween configured to receive the cooling airflow from thecooling hole, wherein the cooling hole is oriented to direct the coolingairflow into the channel, wherein the cooling hole includes an inlet atthe first side of the combustor dome and an outlet at the second side ofthe combustor dome, wherein the heat deflector lip defines an outer tip,and wherein the inlet is positioned a first distance from the centerlineand the outer tip of the heat deflector lip is positioned a seconddistance from the centerline of the combustor assembly, wherein thefirst distance is greater than the second distance; and wherein thesurface of the flange is flush with the second side of the combustordome.
 12. The combustor assembly of claim 11, wherein the cooling holeslants towards the opening in the combustor dome from the first side ofthe combustor dome to the second side of the combustor dome.
 13. Thecombustor assembly of claim 11, wherein the heat deflector lip includesa hot side and a cold side, and wherein the cold side of the heatdeflector lip at least partially defines the circumferential channel.14. The combustor assembly of claim 11, wherein the second side of thecombustor dome is a hot side, and wherein the heat deflector lip of theheat shield at least partially covers the outlet of the cooling hole inthe combustor dome such that the outer tip of the heat deflector lip islocated outward of the outlet of the cooling hole relative to thecenterline of the combustor assembly.
 15. The combustor assembly ofclaim 11, wherein the circumferential channel redirects the coolingairflow from the cooling hole along the second side of the combustordome.
 16. The combustor assembly of claim 11, wherein the combustor domeis formed of a ceramic matrix composite material.
 17. The combustorassembly of claim 1, wherein the flange is positioned adjacent to thesecond side of the combustor dome.
 18. The combustor assembly of claim1, wherein the first side of the combustor dome is a cold side, whereinthe second side of the combustor dome is a hot side, and wherein theoutlet of the cooling hole is positioned at least partially inward ofthe outer tip of the heat deflector lip of the heat shield along adirection of the combustor dome.
 19. The combustor assembly of claim 1,wherein the combustor dome further comprises an inner transition portionand an outer transition portion, and wherein a forward wall extendsbetween the inner transition portion and the outer transition portion.